A gas turbine engine may include a turbine section with multiple rows or stages of stator vanes and rotor blades that interact or react with a high temperature gas flow to create mechanical power. In a gas turbine engine, the turbine rotor blades drive the compressor and, optionally, an electric generator to generate mechanical and/or electrical power.
The efficiency of the engine can be increased by passing a higher temperature gas flow through the turbine. However, the turbine inlet temperature is limited to the vane and blade (airfoils) material properties and the cooling capabilities of these airfoils. The first stage airfoils are exposed to the highest temperature gas flow since these airfoils are located immediately downstream from the combustor. The temperature of the gas flow passing through the turbine progressively decreases as the rotor blade stages extract energy from the gas flow. The leading edge of the vane and blade airfoils is exposed to high temperature gas flow. As a result, the airfoils experience structural loads from thermal expansion/contraction, as well as from fluid forces. The airfoils are desired to be retained in substantially fixed position in order to bear the structural loads. However, the airfoils are also desired to be permitted to move to ameliorate stress and/or strain resulting from thermal expansion/contraction and potential bending and/or cracking.